Plastic gas tank repair

[pyson]

I discovered that my boats' previous owner must have used a reciprocating saw to remove his floor--because the plastic tank has two 3 inch slits cut in it. He repaired it with some sort or hardening liquid--but it was brittle and cracked. It began leaking--and that smell of gas is why I tore the floor up looking for a leak.

I bought some epoxy clay specifically made for plastic gas tank repair and cleaned and roughed up the surrounding plastic. It seems to hold nicely, but I will check for leaks tomorrow.

My question is this---will this be sufficient or would I be better off getting a new tank? It is an under floor 46 gallon tank--I obviously would rather not replace it right now, but I do want the boat to be safe--obviously.

Anybody have any experience with using this clay-epoxy--how does it hold up?

Thanks,

Matt

 

[45Auto]

Re: Plastic gas tank repair

Depends on how much you trust you and your families life to the epoxy. It wouldn't bother me a whole lot in a car where it would leak on the ground if the epoxy fails, but in a boat where it'll be a bomb in the bilge I wouldn't even consider it.

I've had about 40 years of trying to glue plastics together, my experience has pretty much been that if the glue doesn't dissolve the original plastic and "weld" it back together, it's going to peel loose sooner or later. Start flexing a plastic tank around bouncing over wakes and waves it's going to give that epoxy a real test.

I'm not a chemist by any means, maybe the epoxy stuff will work. Just wouldn't be worth it to me to find out it doesn't the hard way.

 

[This_lil_fishy]

Re: Plastic gas tank repair

Depends on how much you trust you and your families life to the epoxy. It wouldn't bother me a whole lot in a car where it would leak on the ground if the epoxy fails, but in a boat where it'll be a bomb in the bilge I wouldn't even consider it.

I've had about 40 years of trying to glue plastics together, my experience has pretty much been that if the glue doesn't dissolve the original plastic and "weld" it back together, it's going to peel loose sooner or later. Start flexing a plastic tank around bouncing over wakes and waves it's going to give that epoxy a real test.

I'm not a chemist by any means, maybe the epoxy stuff will work. Just wouldn't be worth it to me to find out it doesn't the hard way.

Actually, my experience has been that welding plastic is truly the only way to get a solid bond. It involves a soldering iron, and some black plastic zip ties. Use the zip ties as you would solder, melt the plastic of the item you are fixing slightly and melt in the the zip tie. Now, I don't think I would ever try this on a gas tank (heat + gas = BOOM) but just saying....this is how we fix sportbike body panels after a high speed get off.

Ian

 

[Silvertip]

Re: Plastic gas tank repair

Plastic welding is done using a heat gun with a nozzle that concentrates the hot air flow. There are several different types of plastic -- some are compatible and some are not so it is essential that the same material be used for welding as the base material.

 

[pyson]

Re: Plastic gas tank repair

Thanks guys.

I am now starting to worry about the epoxy. I don't know the first thing about "plastic welding" and I don't think a gas tank is the place to start learning.

I was looking at new plastic tanks and 40 + gallon tanks are $250 and up! Oh man...........

 

[redfury]

Re: Plastic gas tank repair

Yeah, gas tanks aren't any fun to replace due to cost. The one thing is though, you can do that work on the gas tank, just remove the fuel, and fill it with water until it overflows, and then remove as much water as you need to keep it from contacting the seam and weld away. Since you won't be using an open flame to ignite the fuel anyway, it's going to be pretty safe with all that water displacing any fuel vapor that might have accumulated in the tank. Once you are done, empty the water from the tank, drip dry as best you can, then either use compressed air to blow out the majority of the moisture, or throw in a bottle of rubbing alcohol and drain that out after sloshing it around to trap the remaining water and reinstall!

You can always do a pressure test on your seam by blowing compressed air into the tank and flexing the repair to see if it holds.

 

[PolishPrince]

Re: Plastic gas tank repair

My vote is for a new tank. All the other repairs boil down to a "patch"
$250 is an investment in safety and a cheap price to insure you're around next season to enjoy your boat.
'nuff said !

 

[pyson]

Re: Plastic gas tank repair

If I do want to replace the tank--how involved is it?

I have a couple of cross beams riveted in place over top of the tank. It also appears to have some foam on the sides from it original factory installation--not sure if it will slip right out. Also, I have about 20 gallons or so of fuel in the tank right now...I think I can get a 50 gallon sealed plastic tank to siphon it into, but not sure how safe that is.

I pressurized the tank with air and the epoxy is holding well, but I am now concerned about how long it will last!

 

[pyson]

Re: Plastic gas tank repair

Nothing?

 

[45Auto]

Re: Plastic gas tank repair

I doubt if anyone will be able to tell you whether your tank is stuck to the foam or not. If you do decide to replace it, you'll just have to dig it out of the foam.

You can siphon the gas out into a 5 gallon can (about $5 at Wal-Mart) and dump it in your car or give it to your friends until it's empty if you're worried about storing it.

 

[pyson]

Re: Plastic gas tank repair

On another note----can I use the gas with oil added I pull from my tank in my car or truck? I didn't think so, but another poster mentioned that it was a possibility.

 

[45Auto]

Re: Plastic gas tank repair

After hurrucane Katrina in 2005 in New Orleans, for several weeks the nearest working gas station was in Baton Rouge, about 100 miles away. I used the 60 gallons of 50:1 pre-mix that was in my boat at the time in my 1997 Saturn (fuel injected 4 cylinder). Couldn't tell any difference. It had 110,000 miles on it at the time, currently has 175,000 and still gets 32 MPG around town and 38 MPG on the highway.

I figured that running the 50:1 was the equivelent of burning a quart of oil per tank of gas. Pretty much the same as dumping in a can of Sea Foam, or Marvel Mystery Oil, or any of the other magic motor fluids. Got lots of friends with ratty cars and trucks that burn a quart of oil per tank anyway whether they want to or not!!!!